Richard godeffroy



(No Model.)

B; GODEFPROY. T-SQUARE;

No. 467,764. Patented Jan. 26, 1892.

2, Fig.4

fly. 9.

[NVENTOR WITNESSES:

STATES PATENT OFFICE.

RICHARD GODEFFROY, OF PHILADELPHIA, PENNSYLVANIA.

T-SQUAREQ SPECIFICATION forming part of Letters Patent No. 467,764, dated January 26, 1892.

' Application filed September 19 1890. Serial No. 365,517. (No model.)

To whom it may concern:

vention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

The invention consists, essentially, of a T- square with an adjustable head, which is firmly held in any required position by a brass bolt, plate, and swivel, and an intermediate ring or disk of some materialfit to increase the friction caused by the pressure of the swivel on the plate, as rubber, leather, cork, &c.

In the accompanying drawings, Figure 1 represents the single-headed T-square in perspective view showing the swivel and plate in fixed position. Fig. 2 represents a section through the center of the head of a singleheaded adjustable T-square; and Fig. 3, a section through the center of the head of a double headed adjustable T square, both showing the manner in which the brass fixtures and frictiomring are applied. In these figures, a is the blade; Z7, the adjustable head, and 0 (only in Fig. 3) the firm head fixed to the blade. d is the bolt with round head (1' and square d 6 is the intermediate frictionring, and f the plate with projecting ring f, formed of two semicircular inclined parts rising from left to right with aprojection at the higher end to prevent the swivel g from slipping over.

Fig. 4 represents a section through the blade of the double-headed T-square close beyond the head.

Figs. 5, 6, 7, and 8 represent, respectively, the top view, side view, cross-section, and inverted view of the plate f in Figs. 2 and 3.

Fig. 9 represents the top view of the friction-ring e in Figs. 2 and 3.

The turning-point of the shifting parts is arranged in such a manner that the main drawing-edge of the square when fixed at right angles to the head will be on the center line of the latter, the adjustable head being straight on both edges and reversible around the turning-point it will allow a firm bearing against the drawing-board at whatever part of the same the T-square may be used. ith the double-headed T-square the fixed head allows a firm bearing of the square against the board when used near the lower edge of the same. The tapered shape of the blade gives it a wide base and great resistance against spring by small weight.

When the T-square has to be adjusted to any angle, the swivel g, Figs. 2 and 3, is turned from right to left, thus releasing the pressure between the adjustable head I) and the blade a. The latter then may be turned to the desired angle and the swivel turned from left to right, thus securing the head and blade absolutely firm in the desired position. In turning the swivel y it slides up the inclined ring f, pressing the plate downward, at the same time the center part of the swivel containing a thread fitting the bolt (Z, and, acting as a nut, screws down on the bolt and pulls the same upward. By this double action the blade and adjustable head in Fig. 2, or the adjustable head and the blade with fixed head in Fig. 3, are firmly drawn together and create a strong pressure 011 the ring 6. The friction between the single parts-viz., blade a, ring 0, and adjustable head bis thus increased in such a manner as to absolutely prevent any involuntary or accidental change in their positions to each other.

I am aware that the single and double headed T-square with adjustable head and the described shape of the same are not new; but

\Vhat I claim as my invention, and wish to secure by Letters Patent, is the following:

In a T-square, the combination of the following elements, to wit: an adjustable head the pivot or turning point of which is formed by a metallic screw-bolt with fiat head, a metallic thumb nut or swivel for the screw-bolt,

consisting of two semicircular parts with insubstantially as set forth and described. 10 clined surfaces, the pitch of which runs in In testimonywhereof I affix rnysignature in a metallic pressure-disk with projecting ring, able head and the blade of the T-square, all

\ opposite direction to that of the thread of the presence of two Witnesses.

5 bolt and on which inclines the flanges or wings RICHARD GODEFFROY. of the thumb-nut bear, the two said inclines WVitnesses:

. being provided with projections at the upper JOHN M. NOBRE,

ends, and a friction-ring between the adjust- EMIL DIEBITSOH. 

